There are numerous cleaning devices that have been employed within the electrographic industry for copier and printer apparatus to remove particulate material, such as toner, carrier, dust, lint, paper fibers, and the like, from various moving surfaces within the apparatus. These surfaces typically include the relatively delicate outer surfaces that function as image-recording and image-transfer elements, as well as the somewhat less delicate surfaces of endless webs that transport sheet material from one image processing station to another.
Blade cleaners are often classified by the way they operate to clean the moving surface they contact. Some operate in a “scraping” mode; others operate in a “wiping” mode. When operating in a scraping mode, the blade element is set at an obtuse angle (typically between 100° and 120°) relative to the oncoming surface it is intended to clean; thus, the blade edge opposes the movement of the surface and deflects particulate material from the surface as it initially engages the blade edge. When operating in a wiping mode, the blade element is set at an acute angle (typically between 60° and 85°) relative to the oncoming surface it is to clean; thus, the blade edge extends slightly in the direction of travel of the moving surface, and particles are wiped from the surface as the web moves away from the blade edge. The scraping mode is harsher on the moving surface and usually requires a lubricant to prevent the blade from becoming unstable and tucking under. In applications where considerable amounts of toner (which serves as a blade lubricant) remain on a surface for cleaning, scraping blades are often preferred since they are more flexible to machine configuration. In applications that require long runs without toner or any other self-lubricating material, wiper blades are preferred due to their inherent stability. Both types of blade cleaners (scrapers and wipers) are disclosed in U.S. Pat. No. 5,426,485 in the names of Fujita, et al., issued Jun. 20, 1995, in which cleaning blades serve to remove particulate material from an endless elastic belt used to convey copy sheets in an electrostatic copier. In this patent, the pressure applied by the blade is adjustable as a function of belt temperature.
U.S. Pat. No. 4,866,483, in the names of Davis, et al., issued Sep. 12, 1989, discloses a blade-type cleaning station for an electrostatic printer having a pair of spaced, parallel cleaning blades, that are set to operate in a wiping mode and serve to remove residual toner from an endless photoconductive image-recording belt once a toner image has been transferred to a copy sheet. The cleaning station further includes a rotatably driven auger for transporting most of the scavenged residual toner collected in a sump to a remote receptacle for removal. The cleaning station is stationary within the printer's base frame, and the entire print engine, including the image-recording belt, is mounted on a pivoting frame for movement between closed and open positions, towards and away from the cleaning station. In its closed position, the print engine's image-recording belt pressingly engages the respective edges of the cleaning blades and is thereby positioned to be cleaned by the blades as the belt advances along its endless path. In its open position, the belt is sufficiently spaced from the blades so that the cleaning station may be readily serviced (by vacuuming scavenged toner from that portion of the sump directly beneath the cleaning blades) or to provide for replacement of the cleaning blades themselves. The blades are loosely supported at opposite ends in a pair of guide channels formed in the end walls of the sump housing. Each blade has a pair of downwardly depending pegs at opposite ends. These pegs fit into the central portion of a coil spring located in each guide channel, such coil springs acting to urge the blades into contact with the moving belt when the print engine frame has been returned to its closed position. In use, the cleaning blades operate on an unsupported region of the image-recording belt.
The cleaning station disclosed in U.S. Pat. No. 4,866,483 provides certain advantages that were not found previously within the prior art, however, problems still exist in certain respects. For example, the sump housing that receives the toner that has been wiped from the belt surface by the blade cleaners is relatively small, thereby requiring the relatively costly auger system to continuously transport particles to a remote location for storage prior to removal. Furthermore, while ready access may be gained to the cleaning station by simply pivoting the print engine frame to its open position, there is no fool-proof way of removing the scavenged particulate material from the sump blade without some potential for blowing the particles throughout the machine frame. Once the print engine has been pivoted to its open position to gain access to the scavenged particle sump for vacuuming, the entire sump is exposed to ambient air, allowing any air currents near the open sump to blow toner or other particulate matter throughout the instrument. Ideally, the scavenged particle sump should be easily removable from the machine frame with scavenged particles remaining confined therein. Once removed, the sump may be discarded and replaced with a new sump, or it may be cleaned at a location safely spaced from the machine and then replaced. Also, since there is no lid or cover on the top of the sump, scavenged particles can escape the sump and contaminate the machine elements while the machine is in operation. Moreover, since there is no hard backup for the web to resist the pressure applied by the cleaning blades, the web is likely to stretch over time, changing the dynamics at the blade edge/web interface.
U.S. Pat. No. 6,453,134, in the names of Ziegelmuller, et al., issued Sep. 17, 2002, discloses an improved blade cleaner having a lid to isolate the removed scavenged particles so that they can not escape the sump and contaminate the machine elements while the machine is in operation, however, U.S. Pat. No. 6,453,134 does not disclose any techniques for simple and easy removal and replacements of the sump assembly.
U.S. Pat. No. 5,991,568, in the names of Ziegelmuller, et al., issued Nov. 23, 1999, discloses a dust seal blade that can be used with either a wiper or a scraper-cleaning blade to increase the effectiveness of the cleaner for dust and lint by allowing toner to build up within the cavity formed by the dust seal blade, the cleaning blade and the surface being cleaned. U.S. Pat. No. 5,991,568 applies a blade with a cavity for a single blade cleaner. Additionally, U.S. Pat. No. 5,991,568 discloses a few techniques for implementing the dust seal blade with a cavity, however, U.S. Pat. No. 5,991,568 does not address the issues presented in a wiper blade configuration. Therefore, there remains a need within the art for an apparatus and an easier method for manufacturing, assembling and servicing wiper blade configurations. Additionally, the wiper blade embodiments are difficult to implement and require further robustness for lint removal than is afforded by a dual blade cleaner approach discussed above.
In view of the foregoing discussion, there remains a need within the art for a dust and lint seal blade that is easy to manufacture, assemble and service and which can further increase the performance of the cleaner under a high level of lint contamination, while providing lubrication for the cleaning blade and oil adsorption from the web.